head (Functional Programming)

Creates a function that returns the first value of an array. Use it with pipe.

const result = pipe(array, head());

INFO

Prefer the original es-toolkit head in ordinary code. Use this fp variant when composing transformations with pipe.

Usage

head returns the first value in the piped array. If the array is empty, it returns undefined.

import { head, pipe } from 'es-toolkit/fp';

pipe([1, 2, 3], head()); // => 1

pipe([], head()); // => undefined

Parameters

This function takes no arguments; call it as head().

Returns

((array: readonly T[]) => T | undefined): A function that maps a readonly T[] to its first value.